LeetCode Weekly Contest 481 Discussion and Solution

Problem-by-Problem Breakdown

Problem 1 - Mirror Distance of an Integer

Approach

Java Code

class Solution {
    public int mirrorDistance(int n) {
        int num = n;
        int rev = 0;

        while(num > 0){
            int digit = num % 10;
            rev = rev * 10 + digit;
            num /= 10;
        }

        return Math.abs(n - rev);
    }
}

Problem 2 - Minimum Deletion Cost to Make All Characters Equal

Approach

Java Code

class Solution {
    public long minCost(String s, int[] cost) {
        int n = cost.length;

        Map<Character, Long> map = new HashMap<>();

        for(int i = 0; i < n; i++){
            char ch = s.charAt(i);

            map.put(ch, (long) map.getOrDefault(ch, 0L) + cost[i]);
        }

        long maxVal = 0;

        for(Long val : map.values()){
            maxVal = Math.max(maxVal, val);
        }

        long ans = 0 - maxVal;

        for(Long val : map.values()){
            ans += val;
        }

        return ans;
    }
}

Problem 3 - Minimum Swaps to Avoid Forbidden Values

Approach

Problem 4 - Total Sum of Interaction Cost in Tree Groups

• Two nodes u and v are considered part of the same group if group[u] == group[v].
• The interaction cost between u and v is defined as the number of edges on the unique path connecting them in the tree.

Approach

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